JP2015029004A - Plasma cvd system and film formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma CVD system which enables the film formation in a low-temperature process of a temperature of 180°C or below while keeping a film-formation speed.SOLUTION: A plasma CVD system of the present invention comprises at least: a first electrode disposed in an internal space of a vacuum processing tank; a second electrode to put a substrate on which is opposed to the first electrode and includes temperature control means; a shower plate provided on the second electrode side of the first electrode to face the substrate; a first power source for applying a high-frequency AC voltage of 2 MHz or higher to the first electrode; a second power source for applying a low-frequency AC voltage of 100 kHz to 1 MHz to the second electrode; means for introducing a processing gas from outside the vacuum processing tank into a space located between the first electrode and the shower plate; and evacuation means for regulating the internal space of the vacuum processing tank to a desired pressure. The distance between a surface of the second electrode on which the substrate is placed and a surface of the shower plate which is opposed to the second electrode is 15-40 mm.

Description

  The present invention relates to a plasma CVD apparatus and a film forming method. More specifically, the present invention relates to a plasma CVD apparatus and a film forming method capable of forming a film at a low process temperature of 180 ° C. or lower.

  In recent years, high integration and high performance of semiconductor elements are required in the semiconductor field. As means for solving these demands, film formation by a plasma CVD (chemical vapor deposition) method, which is expected to be a dense film having excellent step coverage and few defects, has attracted attention.

  In a plasma CVD apparatus, a source gas is decomposed using plasma, and, for example, a thin film is formed on a film formation surface of a substrate. In this plasma CVD apparatus, for example, by a shower plate having a plurality of jet holes, the space in the chamber is divided into a film formation space (reaction chamber) in which the substrate is disposed and a gas introduction space into which the source gas is introduced It is divided. The chamber is connected to a high frequency power source, and the shower plate functions as a cathode electrode. The gas introduced into the gas introduction space is uniformly ejected from the respective ejection ports of the shower plate into the film formation space. At this time, plasma of the source gas is generated in the film formation space, and the source gas decomposed by the plasma reaches the film formation surface of the substrate to form a desired film on the substrate (for example, Patent Document 1). ). In such a plasma CVD apparatus, film formation is performed at a high temperature of, for example, 300 ° C. or higher.

By the way, in recent years, semiconductor devices have been reduced in size and thickness, and accordingly, the thickness of a base material (such as a glass substrate) used tends to be reduced.
However, when plasma CVD film formation is performed at a high temperature using a thin glass substrate, the glass substrate may be damaged, such as warping or cracking. In addition, when the glass substrate is a laminated substrate bonded using an adhesive or the like, depending on the type of the adhesive, the adhesive force may be reduced due to film formation at a high temperature, and the substrate may be peeled off.
On the other hand, when the film forming process is performed at a low temperature, there is a problem that the film forming speed is slowed down.

JP 2002-280377 A

The present invention has been devised in view of such a conventional situation, and provides a plasma CVD apparatus capable of forming a film at a lower process temperature (for example, 180 ° C. or lower) while maintaining the film forming speed. The primary purpose is to do.
The second object of the present invention is to provide a film forming method capable of forming a film at a lower process temperature (for example, 180 ° C. or lower) while maintaining the film forming speed using a plasma CVD apparatus. And

The plasma CVD apparatus according to claim 1 of the present invention includes a first electrode (upper electrode) disposed in an internal space of a vacuum processing tank, and a counter electrode disposed in the internal space so as to face the first electrode. A second electrode (lower electrode) in which a temperature control means is placed, a shower plate provided on the second electrode side of the first electrode and disposed opposite to the base, and the first A first power source for applying a high frequency AC voltage of 2 MHz or higher to the electrode; a second power source for applying a low frequency AC voltage of 100 kHz to 1 MHz to the second electrode; the first electrode and the shower plate And a means for introducing process gas from the outside of the vacuum processing tank, and an exhaust means for adjusting the internal space of the vacuum processing tank to a desired pressure. In the CVD apparatus, a distance (T / S) between a surface of the second electrode on which the substrate is placed and a surface of the shower plate facing the second electrode is 15 mm or more and 40 mm or less. It is characterized by.
A film forming method according to a second aspect of the present invention is a film forming method for forming a silicon oxide film on a substrate (surface to be processed) using the plasma CVD apparatus according to the first aspect, wherein a process gas is formed. Tetraethoxysilane (TEOS for short, tetraethyl silicate Si (OC ₂ H ₅ ) ₄ ) or monosilane is used as a raw material, and the substrate temperature [° C.] during film formation is (150 or more) 180 or less. It is characterized by.
The film forming method according to claim 3 of the present invention is the film forming method according to claim 2, wherein a film formation rate [nm / min] for forming a silicon oxide film on the substrate is 80 or more and 360 or less. It is characterized by that.

According to the plasma CVD apparatus according to claim 1 of the present invention, the interval (T / S) between the surface of the second electrode on which the substrate is placed and the surface of the shower plate facing the second electrode is 15 mm or more and 40 mm. By making the following, the space where the introduced process gas exists becomes wider. That is, more gas can be introduced into the internal space, which facilitates decomposition of the process gas. As a result, it is possible to efficiently form a film even in a lower temperature range (180 ° C. or lower) than the conventional one (190 ° C. or higher). Therefore, the present invention can provide a plasma CVD apparatus capable of forming a film at a lower process temperature (for example, 180 ° C. or lower). In particular, the plasma CVD apparatus of the present invention contributes to the formation of a silicon oxide film having excellent breakdown voltage (BV) characteristics.
According to the film forming method of the present invention, the distance (T / S) between the surface of the second electrode on which the substrate is placed and the surface of the shower plate facing the second electrode is 15 mm. By using a plasma CVD apparatus having a thickness of 40 mm or less, the space where the introduced process gas exists can be widened. That is, more gas can be introduced into the internal space, which facilitates decomposition of the process gas. As a result, it is possible to efficiently form a film even in a lower temperature range (180 ° C. or lower) than the conventional one (190 ° C. or higher). As a result, the present invention can provide a plasma CVD method capable of forming a film at a lower process temperature (for example, 180 ° C. or lower) while maintaining the film formation rate. In particular, the film forming method of the present invention contributes to the formation of a silicon oxide film having excellent breakdown voltage (BV) characteristics.
Further, with the configuration of claim 2, by changing the bias power without changing the film formation rate, the internal stress [MPa], which is one of the characteristics of the thin film obtained, is + (plus) 200. It can be controlled over a wide range in the range of ˜0 to − (minus) 150.
According to the film forming method of the present invention, the film forming rate [nm / min] can be improved to about 4.5 times as high as 80 to 360 only by changing the TEOS flow rate. Is also possible. In this range, by changing the bias power, the internal stress, which is one of the characteristics of the obtained thin film, can be controlled in a wide range from + (plus) to 0- (minus).

It is a schematic sectional drawing which shows the structure of the plasma processing apparatus in embodiment of this invention. It is a figure which shows the relationship between T / S and the breakdown voltage (BV) of the obtained thin film using the plasma CVD apparatus of this invention. It is the figure which showed the relationship between the bias power applied using the plasma CVD apparatus of this invention, and the internal stress of the obtained thin film. It is a figure which shows the relationship between the flow volume of TEOS and the film-forming speed | velocity | rate using the plasma CVD apparatus of this invention. It is a figure which shows a current-voltage characteristic in the conventional plasma CVD apparatus and the plasma CVD apparatus of this invention. It is a photograph which shows a mode that the thin film was formed inside the micropore using the plasma CVD apparatus of this invention.

Hereinafter, embodiments of a plasma CVD apparatus according to the present invention will be described with reference to the drawings.
In the drawings used for the following description, the dimensions and ratios of the respective components are appropriately changed from the actual ones in order to make the respective components large enough to be recognized on the drawings.

FIG. 1 is a schematic cross-sectional view showing a configuration of a plasma CVD apparatus 1 in the present embodiment.
The plasma CVD apparatus according to the present embodiment has a first electrode (upper electrode) disposed in the internal space of the vacuum processing tank, and is disposed to face the first electrode in the internal space, and places a substrate (object to be processed) thereon. A second electrode (lower electrode) having a temperature control means, a shower plate provided on the second electrode side of the first electrode and arranged to face the base, and a high-frequency AC voltage of 2 MHz or more with respect to the first electrode In the space located between the first power source to be applied, the second power source to apply a low frequency AC voltage of 100 kHz to 1 MHz to the second electrode, and the first electrode and the shower plate, At least a means for introducing a process gas from the outside and an exhaust means for adjusting the internal space of the vacuum processing tank to a desired pressure are provided.
And in the plasma CVD apparatus of this embodiment, the space | interval (T / S) of the surface which mounts a base | substrate in a 2nd electrode, and the surface which opposes a 2nd electrode in a shower plate is 15 mm or more and 40 mm or less.

  As shown in FIG. 1, the plasma CVD apparatus 1 includes a processing chamber 101 having a film formation space (internal space) 2a which is a reaction chamber. The processing chamber 101 includes a vacuum chamber (vacuum processing tank) 2, an electrode flange (first electrode (upper electrode)) 4, and an insulating flange 81. The insulating flange 81 is sandwiched between the vacuum chamber 2 and the electrode flange 4.

  An opening is formed in the bottom 11 of the vacuum chamber 2. A support column 25 is inserted into the opening, and the support column 25 is disposed in the lower portion of the vacuum chamber 2. A second electrode (support portion, lower electrode) 15 is connected to the tip of the support column 25 (in the vacuum chamber 2). The second electrode 15 includes a plate heater (temperature control means) 16. Further, an exhaust pipe 27 is connected to the vacuum chamber 2. A vacuum pump 28 is provided at the tip of the exhaust pipe 27. The vacuum pump 28 reduces the pressure so that the inside of the vacuum chamber 2 is in a vacuum state.

  The support column 25 is connected to an elevating mechanism (not shown) provided outside the vacuum chamber 2, and can move up and down in the vertical direction of the base body (object to be processed) 10. In other words, the second electrode 15 connected to the tip of the support column 25 is configured to be movable up and down. A bellows (not shown) is provided outside the vacuum chamber 2 so as to cover the outer periphery of the support column 25.

The electrode flange 4 has an upper wall 41 and a peripheral wall 43. The electrode flange 4 is disposed so that the opening is positioned below in the vertical direction of the base body 10. A shower plate 5 is attached to the opening of the electrode flange 4. Thereby, a space 24 is formed between the electrode flange 4 and the shower plate 5.
The electrode flange 4 has an upper wall 41 that faces the shower plate 5. A gas inlet 42 is provided in the upper wall 41.
In addition, a gas introduction pipe 7 is provided between the process gas supply unit 21 and the gas introduction port 42 provided outside the processing chamber 101. One end of the gas introduction pipe 7 is connected to the gas introduction port 42, and the other end is connected to the process gas supply unit 21. Process gas is supplied from the process gas supply unit 21 to the space 24 through the gas introduction pipe 7. That is, the space 24 functions as a gas introduction space into which process gas is introduced.

  The electrode flange 4 and the shower plate 5 are each made of a conductive material, and the electrode flange 4 is electrically connected to an RF power source (first power source) 9 provided outside the processing chamber 101. The RF power source 9 is a high frequency power source that applies a high frequency AC voltage of 2 MHz or more to the electrode flange 4. That is, the electrode flange 4 and the shower plate 5 are configured as cathode electrodes. A plurality of gas jets 6 are formed in the shower plate 5. The process gas introduced into the space 24 is ejected from the gas ejection port 6 into the film formation space 2 a in the vacuum chamber 2.

The process gas introduced from the process gas supply unit 21 into the space 24 through the gas introduction pipe 7 and the gas introduction port 42 is ejected into the vacuum chamber 2 through the gas ejection port 6 of the shower plate 5.
The space 24 is a space on the upstream side of the shower plate 5, and the inside of the vacuum chamber 2 is a space on the downstream side of the shower plate 5.

  The second electrode 15 is a plate-like member having a flat surface. The base body 10 is placed on the upper surface of the second electrode 15. The second electrode 15 functions as a ground electrode, that is, an anode electrode.

When the process gas is ejected from the gas ejection port 6 in a state where the substrate 10 is disposed on the second electrode 15, the process gas is supplied to the space on the processing surface 10 a of the substrate 10.
A heater 16 is provided inside the second electrode. The temperature of the second electrode is adjusted to a predetermined temperature by the heater.

  Further, a plurality of grounds 30 are arranged at substantially equal intervals on the outer peripheral edge of the second electrode 15 so as to connect the second electrode 15 and the vacuum chamber 2. The ground 30 is made of, for example, a nickel-based alloy or an aluminum alloy.

A second power source 17 is connected to the second electrode 15. The second power source 17 is a high frequency power source that applies a low frequency AC voltage (bias voltage) of 100 kHz to 1 MHz. When the plasma is generated in the film formation space 2a, the second electrode that receives the AC voltage functions as a negative potential with respect to the plasma space, that is, as a cathode, and draws the ionic particles into the substrate 10 so that the ionic particles travel straight with respect to the substrate 10. Improve sexiness. As a result, the source gas decomposed by the plasma can be smoothly fed toward the substrate, and the film formation speed or the orientation of the thin film is improved.
Thereby, when forming a thin film inside the structure (for example, micropore) which has a high aspect ratio, the coverage (coverage) of a thin film can be improved.
Further, for example, as shown in Examples described later, by changing the bias power without changing the film formation rate, the internal stress, which is one of the characteristics of the obtained thin film, is changed from + (plus) to 0. It can be controlled over a wide range in the range of-(minus).

And in the plasma CVD apparatus 1 of this embodiment, the space | interval (T / S) of the upper surface 15a which mounts the base | substrate 10 in the 2nd electrode 15, and the surface 5a which opposes the 2nd electrode 15 in the shower plate 5 is set. It is 15 mm or more and 40 mm or less.
According to the plasma CVD apparatus 1 of the present embodiment, the distance (T / S) between the surface 15a on which the substrate 10 is placed in the second electrode 15 and the surface 5a facing the second electrode 15 in the shower plate 5 is By setting it to 15 mm or more and 40 mm or less, the space where the introduced process gas exists becomes wide. That is, a large amount of gas can be introduced into the film formation space 2a, thereby promoting the decomposition of the process gas. As a result, the film can be efficiently formed even at a low temperature. As a result, the plasma CVD apparatus 1 of the present invention can efficiently form a film even in a lower temperature range (180 ° C. or lower) than the conventional one (190 ° C. or higher) while maintaining the film forming speed. In particular, the plasma CVD apparatus 1 of the present invention contributes to the formation of a silicon oxide film having excellent breakdown voltage (BV) characteristics.

Specifically, as shown in the examples described later, by setting T / S in the range of 15 mm to 40 mm, it is one of the characteristics of the thin film obtained using this plasma CVD apparatus 1. The breakdown voltage (BV) can be greatly improved.
That is, the breakdown voltage of the thin film can be increased by increasing T / S within the above range. When T / S is smaller than 15 mm, the breakdown voltage of the obtained thin film becomes small. On the other hand, if T / S is larger than 40 mm, the effect of improving the breakdown voltage cannot be obtained sufficiently.
Thereby, in this CVD film-forming apparatus 1, film formation can be performed at a lower temperature (for example, 200 ° C. or lower) than the conventional one while maintaining the characteristics of the obtained film.

Next, an operation when a thin film is formed on the processing surface 10a of the substrate 10 using the plasma CVD apparatus 1 will be described. Here, a case where a silicon oxide film is formed as a thin film will be described as an example.
First, the vacuum chamber 2 is depressurized using the vacuum pump 28.
With the vacuum chamber 2 maintained in a vacuum, the substrate 10 is carried into the film formation space 2 a in the vacuum chamber 2 and placed on the second electrode 15.
Here, the second electrode 15 is positioned below the vacuum chamber 2 before the substrate 10 is placed. That is, before the base 10 is carried in, the distance between the second electrode 15 and the shower plate 5 is wide, so that the base 10 can be easily placed on the second electrode 15 using a robot arm (not shown). Can be placed.

  After the base body 10 is placed on the second electrode 15, an elevating mechanism (not shown) is activated, the support column 25 is pushed upward, and the base body 10 placed on the second electrode 15 also moves upward. To do. As a result, the distance between the shower plate 5 and the substrate 10 is determined as desired so that the distance is necessary for proper film formation, and this distance is maintained. Here, the distance between the shower plate 5 and the base 10 is maintained at a distance suitable for forming a film on the base 10.

  Specifically, the distance (T / S) between the upper surface 15a on which the substrate 10 is placed in the second electrode 15 and the surface 5a facing the second electrode 15 in the shower plate 5 is set to 15 mm or more and 40 mm or less. . Thereby, the space where the introduced process gas exists can be widened. That is, a large amount of gas can be introduced into the film formation space 2a, thereby promoting the decomposition of the process gas. As a result, it is possible to efficiently form a film even in a lower temperature range (180 ° C. or lower) than the conventional one (190 ° C. or higher). As a result, film formation can be performed at a lower process temperature (for example, 180 ° C. or lower) while maintaining the film formation rate.

Thereafter, the process gas is introduced into the first space 24 a from the process gas supply unit 21 through the gas introduction pipe 7 and the gas introduction port 42.
In particular, in the present embodiment, tetraethoxysilane (abbreviated as TEOS, tetraethyl silicate (Si (OC ₂ H ₅ ) ₄ ) or monosilane (SiH ₄ ) is used as a raw material of the process gas. A silicon oxide film can be formed, and the film formation rate can be improved by increasing the flow rate of the process gas, that is, high-speed film formation can be realized.
Subsequently, the process gas is supplied to the film formation space 2 a in the vacuum chamber 2 through the gas ejection port 6 of the shower plate 5.
At this time, the pressure Pe in the film formation space 2 a is reduced by the conductance A of the shower plate 5.

Next, the RF power source 9 is activated to apply a high frequency voltage to the electrode flange 4.
At this time, the electrode flange 4 is electrically insulated from the vacuum chamber 2 via the insulating flange 81. The vacuum chamber 2 is grounded.
In such a structure, a high frequency voltage is applied between the shower plate 5 and the second electrode 15 to generate a discharge, and between the shower plate 5 provided on the electrode flange 4 and the processing surface 10a of the base 10. Plasma is generated.

The process gas is decomposed in the plasma generated in this way to obtain a plasma process gas, a vapor phase growth reaction occurs on the processing surface 10a of the substrate 10, and a thin film is formed on the processing surface 10a. At this time, by applying a bias voltage to the substrate 10 from the second power source 17, the source gas decomposed by the plasma can be smoothly fed toward the substrate, and the film formation speed or the orientation of the thin film is improved.
Specifically, in the film formation method of the present embodiment, the film formation rate [nm / min] for forming the silicon oxide film on the substrate 10 is 80 or more and 360 or less. According to the film formation method of the present embodiment, the film formation rate [nm / min] can be increased to about 80 to 360, or about 4.5 times, simply by changing the TEOS flow rate. In this range, by changing the bias power, the internal stress, which is one of the characteristics of the obtained thin film, can be controlled in a wide range from + (plus) to 0- (minus).

Using a device as shown in FIG. 1, a silicon oxide film was formed and its characteristics were evaluated.
(Deposition conditions)
Unless otherwise specified, the film forming conditions were as follows.
As the substrate, a silicon substrate having a diameter of 300 mm or a glass bonding substrate was used. The RF power output of the RF power source 9 was 1000 W. The bias output was 200W. The distance (T / S) between the substrate mounting surface 15a of the second electrode 15 and the surface 5a of the shower plate was set to 30 mm. The temperature of the second electrode (heater) was 130 ° C.
Further, a silicon oxide film was formed on the processing surface 10a of the base 10 so that the pressure in the film formation space 2a was 100 Pa.
Note that a mixed gas of 30 (sccm) TEOS and 850 (sccm) O ₂ (oxygen) was used as the type and flow rate of the process gas introduced into the space 24 from the process gas supply unit 21.

FIG. 2 is a graph showing the relationship with the breakdown voltage (BV) of the thin film obtained by changing the T / S.
As is apparent from FIG. 2, it can be seen that as the T / S increases, the breakdown voltage of the obtained thin film increases. In particular, when the T / S is in the range of 15 mm to 40 mm, the breakdown voltage of the thin film can be greatly improved.

FIG. 3 is a graph showing the relationship with the internal stress of the thin film obtained by changing the applied bias power.
As can be seen from FIG. 3, by changing the bias power, the internal stress, which is one of the characteristics of the obtained thin film, can be controlled in a wide range from + (plus) to 0-(minus). I understand. At this time, even when the bias power is changed, the film forming speed is hardly changed.

FIG. 4 is a graph showing the relationship between the TEOS flow rate and the film formation rate when film formation is performed while changing the TEOS flow rate.
As is apparent from FIG. 4, it can be seen that by increasing the flow rate of the process gas, the film formation rate [nm / min] is improved by about 4.5 times to 80 to 360. That is, high-speed film formation can be realized. 3 and 4, the internal stress, which is one of the characteristics of the thin film obtained by changing the bias power when the film formation rate [nm / min] is in the range of 80 to 360, is expressed as + ( It can be seen that a wide range of control is possible in the range of (plus) to 0 to-(minus).

FIG. 5 shows a conventional plasma CVD apparatus in which the distance (E / S) between the surface to be processed of the substrate and the shower plate is a narrow edge of 14 mm, the surface on which the substrate is placed on the second electrode, and the shower plate 5 is a graph showing the results of evaluating the current-voltage characteristics of the silicon oxide films produced using the plasma CVD apparatus of the present invention in which the distance (T / S) between the second electrode and the surface facing the second electrode is 30 mm. is there.
Further, film formation was carried out at a film formation rate in the plasma CVD apparatus of the present invention, and film characteristics (internal stress, yield voltage) were evaluated for the obtained thin film. The results are shown in Table 1. The breakdown voltage shown in Table 1 is for 1 × 10 ⁻⁸ [A / cm ² ].

From FIG. 5 and Table 1, the following points became clear.
(A1) From FIG. 5, according to the plasma CVD apparatus of the present invention, the temperature of the stage (second electrode) is 130 ° C. (the temperature of the substrate is 150 ° C.), which is a film formation at a lower temperature than the conventional one. It can also be seen that the breakdown voltage of the resulting thin film can be significantly improved. For example, when realizing a withstand voltage of 2 [MV / cm], a silicon oxide film manufactured using a conventional apparatus requires about 10 ⁻⁵ [A / cm ² ]. In contrast, the silicon oxide film manufactured using the apparatus of the present invention can be remarkably reduced to about 10 ⁻⁸ [A / cm ² ] or less. Even with a breakdown voltage of 5 [MV / cm], which is considered to be the next generation, it can be achieved at about 10 ⁻⁵ [A / cm ² ] with a silicon oxide film manufactured using the apparatus of the present invention.
(A2) From Table 1, it was found that by lowering the deposition rate, the internal stress of the produced silicon oxide film doubled and the breakdown voltage increased 23 times. According to the apparatus of the present invention, a silicon oxide film having such characteristics can be formed at a lower temperature (180 ° C. or lower) than the conventional one.
From the above results, according to the plasma CVD apparatus and the film forming method using the same according to the present invention, it is possible to form a film at a lower process temperature (for example, 180 ° C. or lower) while maintaining the film forming speed. Was confirmed.

Next, using the CVD film forming apparatus shown in FIG. 1, a silicon oxide film is formed in a micro hole (trench) having a diameter of 10 μm and a depth of 55 μm, and the film thickness and coverage of the thin film in each part of the hole Evaluated.
Note that TEOS was used as the process gas, and the substrate temperature was 180 ° C. The film formation rate was 150 nm / min or more.
FIG. 6 is a photograph of a side cross section showing a state in which a thin film has been formed inside the micropore. The photograph on the left is a fine hole located at the center (center) of the substrate, and the photograph on the right is a fine hole located at the peripheral edge (edge) of the substrate. In the left and right photographs, the lower part is an enlarged photograph showing the vicinity of the bottom in the upper fine hole.
Here, the central portion (center) of the substrate is the vicinity of the intersection of diagonal lines in the above-described rectangular substrate (longitudinal mm × horizontal mm glass substrate), and the peripheral portion (edge) of the substrate is the side surface of the substrate It is near the point of mm from the inside.

Table 2 shows the film thickness and coverage of the thin film at the periphery and inside of the opening of the micropore, as measured from the photograph of FIG. Here, the “coverage” is a numerical value obtained by dividing the film thickness at each measurement position by the film thickness at the top and multiplying by 100.
The film thickness of the thin film at the periphery and inside of the opening of the fine hole was measured at the following five positions.
Top: Position of the periphery of the opening on the surface on which the opening of the fine hole is arranged.
Top side: A depth position of about ¼ when viewed from the opening side on the inner surface of the micropore.
Middle side: A depth position of about ½ when viewed from the opening side on the inner surface of the micropore.
Bottom side: A depth position of about 3/4 when viewed from the opening side on the inner surface of the micropore.
Bottom: The position of the central portion on the inner bottom surface of the micropore.

The following points became clear from FIG. 6 and Table 2.
(B1) From the photograph shown in FIG. 6, by using the apparatus of the present invention, the thin film could be formed to the bottom of the hole even when the thin film was formed inside the fine hole having a high aspect ratio.
(B2) Compared with the periphery of the opening, a coverage of about 20% was obtained also on the inner surface and inner bottom surface of the micropore.
Therefore, the plasma CVD apparatus and the film forming method using the same according to the present invention have excellent coverage at a low temperature of 180 ° C. or lower with respect to the inside (inner side surface and inner bottom surface) of the micropore having a high aspect ratio. This contributes to the formation of a dense film with few defects.

From the above results, the conventional method required a high temperature of 200 ° C. or higher, but according to the present invention, for example, the film can be formed at a significantly lower temperature than that of the conventional method, for example, 180 degrees or less. It is also possible to achieve good film quality with excellent breakdown voltage characteristics.
In particular, it is possible to improve the film formation rate to about 4.5 times only by changing the TEOS flow rate. In this range, it is also possible to control the internal stress, which is one of the characteristics of the obtained thin film, in a wide range from + (plus) to 0 to-(minus) by changing the bias power. It was confirmed that there was.

  The embodiments of the present invention have been described with specific examples. However, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications are made without departing from the spirit of the present invention. It is possible.

  As described above in detail, the present invention is applicable to a plasma CVD apparatus and a film forming method using the same.

  DESCRIPTION OF SYMBOLS 1 Plasma CVD apparatus, 2 Vacuum chamber (vacuum processing tank), 2a Film-forming space (internal space), 4 Electrode flange (1st electrode), 5 Shower plate, 5a surface, 6 Gas ejection port, 7 Gas introduction pipe, 9 RF power source (first power source), 10 substrate (object to be processed), 10a processing surface, 24 space, 15 second electrode (anode electrode), 15a surface, 16 heater (temperature control means), 17 second power source, 21 process Gas supply unit, 42 gas inlet, 81 insulating flange, 101 processing chamber.

Claims (3)

A first electrode disposed in the internal space of the vacuum processing tank;
A second electrode disposed opposite to the first electrode in the internal space, on which the substrate is placed and which has a temperature control means;
A shaft provided on the second electrode side of the first electrode and disposed opposite to the base. A warplate,
A first power source for applying a high-frequency AC voltage of 2 MHz or higher to the first electrode;
A second power source for applying a low-frequency AC voltage of 100 kHz to 1 MHz to the second electrode;
Means for introducing a process gas from the outside of the vacuum processing tank into the space located between the first electrode and the shower plate;
Exhaust means for adjusting the internal space of the vacuum processing tank to a desired pressure;
A plasma CVD apparatus comprising at least
A plasma CVD apparatus characterized in that an interval (T / S) between a surface of the second electrode on which the substrate is placed and a surface of the shower plate facing the second electrode is 15 mm or more and 40 mm or less. . A film forming method for forming a silicon oxide film on a substrate using the plasma CVD apparatus according to claim 1,
Tetraethoxysilane or monosilane is used as a raw material for the process gas,
A film forming method, wherein the temperature [° C.] of the substrate during film formation is 180 or less. The film forming method according to claim 2,
A film formation method, wherein a film formation rate [nm / min] for forming a silicon oxide film on the substrate is 80 or more and 360 or less.